Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for generating a projection-based frame, comprising: receiving an omnidirectional video frame corresponding to a viewing sphere; and generating, by a conversion circuit, the projection-based frame according to the omnidirectional video frame and an octahedron projection layout, wherein the projection-based frame has a 360-degree image content represented by triangular projection faces assembled in the octahedron projection layout, and a 360-degree image content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere; wherein the triangular projection faces assembled in the octahedron projection layout comprise a first triangular projection face, a second triangular projection face and a third triangular projection face, one side of the first triangular projection face has contact with one side of the second triangular projection face, one side of the third triangular projection face has contact with another side of the second triangular projection face, there is an image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, and there is an image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face; wherein the triangular projection faces of the octahedron projection layout are obtained from the octahedron projection of the viewing sphere according to an octahedron; a boundary between one side of a first face of the octahedron and one side of a second face of the octahedron corresponds to the image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, where said one side of the first face of the octahedron connects with said one side of the second face of the octahedron; and a boundary between one side of a third face of the octahedron and another side of the second face of the octahedron corresponds to the image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face, where said one side of the third face of the octahedron connects with said another side of the second face of the octahedron.
This invention relates to the field of omnidirectional video processing, specifically methods for generating projection-based frames from omnidirectional video data. The problem addressed is the efficient representation and projection of 360-degree video content, which requires specialized mapping techniques to avoid distortion and maintain image continuity. The method involves receiving an omnidirectional video frame representing a viewing sphere and generating a projection-based frame using an octahedron projection layout. The projection-based frame consists of triangular projection faces assembled in an octahedron configuration, where the 360-degree image content of the viewing sphere is mapped onto these triangular faces. The triangular faces include a first, second, and third face, where adjacent faces share sides with continuity boundaries to ensure seamless image transitions. The octahedron projection layout is derived from an octahedron, where the boundaries between adjacent faces of the octahedron correspond to the continuity boundaries between the triangular projection faces in the final frame. This approach ensures accurate mapping of spherical content onto a planar representation while minimizing distortion and maintaining visual coherence. The method is particularly useful for applications requiring efficient storage, transmission, or processing of omnidirectional video data.
2. The method of claim 1 , wherein the triangular projection faces assembled in the octahedron projection layout further comprise a fourth triangular projection face, one side of the fourth triangular projection face has contact with yet another side of the second triangular projection face, and there is an image content continuity boundary between said one side of the fourth triangular projection face and said yet another side of the second triangular projection face.
This invention relates to a method for assembling triangular projection faces into an octahedron projection layout, particularly for creating seamless panoramic or immersive visual displays. The problem addressed is the need to ensure image content continuity across adjacent triangular projection faces in an octahedral arrangement, which is commonly used in projection-based virtual reality, dome displays, or other wide-angle visualization systems. The method involves arranging multiple triangular projection faces in an octahedron layout, where each triangular face is positioned to form a three-dimensional geometric structure resembling an octahedron. The arrangement includes a second triangular projection face adjacent to a first triangular projection face, with their respective sides in contact. Additionally, a fourth triangular projection face is included, where one side of this fourth face contacts another side of the second triangular face. The key innovation is the inclusion of an image content continuity boundary between the contacting sides of the fourth and second triangular faces. This boundary ensures that the visual content displayed across these adjacent faces aligns seamlessly, preventing visible discontinuities or gaps in the projected image. The method is particularly useful in applications requiring high-resolution, distortion-free panoramic displays, such as planetariums, flight simulators, or immersive virtual reality environments. The seamless integration of multiple projection faces enhances the overall visual experience by maintaining image coherence across the entire display surface.
3. The method of claim 1 , wherein a shape of each of the triangular projection faces is an equilateral triangle.
This invention relates to a method for manufacturing a three-dimensional object using a projection-based additive manufacturing process. The method addresses the challenge of improving the structural integrity and precision of printed objects by optimizing the geometry of the projection faces used during the layer-by-layer build process. Specifically, the method involves projecting light onto a build surface to selectively cure a photopolymer resin, where the projected light forms triangular projection faces. These triangular faces are arranged to form a three-dimensional lattice structure, with each triangular face being an equilateral triangle. The equilateral triangle shape ensures uniform stress distribution and consistent mechanical properties across the printed object. The method also includes adjusting the size and orientation of the triangular faces to control the density and porosity of the final structure, allowing for customization of material properties such as stiffness and flexibility. By using equilateral triangles, the method enhances the structural stability of the printed object while maintaining high precision in the layer-by-layer deposition process. This approach is particularly useful in applications requiring lightweight yet strong components, such as aerospace, automotive, and medical devices.
4. The method of claim 3 , wherein each of the triangular projection faces has a first side, a second side and a third side, and an equator of the viewing sphere is mapped along first sides of the triangular projection faces.
This invention relates to a method for projecting a spherical image onto a plurality of triangular projection faces, addressing the challenge of efficiently mapping spherical content onto planar surfaces for display or processing. The method involves arranging multiple triangular projection faces in a specific configuration to minimize distortion when projecting a spherical image, such as a 360-degree panoramic view, onto these faces. Each triangular projection face has three sides, and the equator of the viewing sphere is aligned with the first sides of these triangular faces. This alignment ensures that the equatorial region of the spherical image is accurately mapped without distortion. The triangular faces are arranged such that their second and third sides form a continuous boundary, allowing seamless stitching of the projected image segments. The method may also include adjusting the projection parameters to optimize image quality and reduce artifacts. This approach is particularly useful in applications requiring high-fidelity spherical image projection, such as virtual reality, panoramic displays, and immersive media systems. The invention improves upon existing projection techniques by providing a more efficient and distortion-minimized mapping of spherical content onto planar surfaces.
5. The method of claim 3 , wherein an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces.
This invention relates to a method for projecting a viewing sphere onto a polyhedral surface, specifically addressing the challenge of minimizing distortion when mapping spherical content onto flat or planar faces. The method involves projecting the viewing sphere onto a polyhedral surface composed of multiple triangular projection faces, where each triangular face is a portion of the viewing sphere. A key aspect is that the equator of the viewing sphere is not aligned with any side of the triangular projection faces, which helps reduce distortion in the projected image. This approach ensures that the projection maintains a more uniform distribution of visual data across the polyhedral surface, improving clarity and reducing geometric inaccuracies. The method may also include adjusting the projection to account for the curvature of the viewing sphere, ensuring that the mapped content accurately represents the original spherical image. The triangular faces are arranged in a way that optimizes coverage while avoiding alignment with the equator, which can introduce distortion. This technique is particularly useful in applications requiring high-fidelity spherical projections, such as virtual reality, panoramic imaging, or 3D mapping systems.
6. The method of claim 3 , wherein the viewing sphere is composed of a first hemisphere and a second hemisphere; and the first triangular projection face, the second triangular projection face and the third triangular projection face are all derived from the first hemisphere via the octahedron projection of the viewing sphere.
This invention relates to a method for generating triangular projection faces from a viewing sphere, particularly in the field of computer graphics or virtual reality. The problem addressed is the efficient and accurate representation of a spherical viewing space using triangular faces derived from an octahedron projection. The method involves dividing the viewing sphere into two hemispheres: a first hemisphere and a second hemisphere. The triangular projection faces are generated exclusively from the first hemisphere using an octahedron projection technique. This projection method maps the spherical surface onto an octahedron, which is then subdivided into triangular faces. The first, second, and third triangular projection faces are derived from this subdivision, ensuring accurate spatial representation while minimizing distortion. The use of an octahedron projection allows for a structured and symmetric approach to mapping the spherical surface, which is particularly useful in applications requiring high-fidelity 3D rendering or virtual environment navigation. The method ensures that the triangular faces maintain geometric consistency, reducing computational complexity and improving rendering performance. This approach is beneficial in fields such as virtual reality, augmented reality, and 3D modeling, where precise spatial representation is critical.
7. The method of claim 6 , wherein the triangular projection faces assembled in the octahedron projection layout further comprise a fourth projection face derived from the first hemisphere via the octahedron projection of the viewing sphere, one side of the fourth triangular projection face has contact with another side of the third triangular projection face, and there is an image content discontinuity boundary between said one side of the fourth triangular projection face and said another side of the third triangular projection face.
This invention relates to a method for generating and arranging triangular projection faces in an octahedron projection layout to represent a viewing sphere, particularly addressing the challenge of minimizing image distortion and discontinuities in spherical projections. The method involves deriving multiple triangular projection faces from a hemisphere of the viewing sphere using an octahedron projection technique. These triangular faces are assembled into an octahedron layout, where each face corresponds to a segment of the spherical surface. The arrangement includes a fourth triangular projection face derived from the first hemisphere, which is positioned adjacent to a third triangular projection face. A key feature is the presence of an image content discontinuity boundary between the contacting sides of the fourth and third triangular faces, ensuring seamless or controlled transitions in the projected image. This approach improves the accuracy and continuity of spherical projections by systematically organizing the triangular segments and managing discontinuities at their boundaries. The method is particularly useful in applications requiring high-fidelity spherical mapping, such as virtual reality, panoramic imaging, or computer graphics.
8. The method of claim 6 , wherein a shape of the octahedron projection layout is a rectangle, the triangular projection faces assembled in the octahedron projection layout further comprise a fourth projection face derived from the first hemisphere via the octahedron projection of the viewing sphere, the fourth projection face is split into a first right-triangle-shaped part and a second right-triangle-shaped part, the first right-triangle-shaped part has a first side being one side of the fourth projection face and a second side being a first part of another side of the fourth projection face, the second right-triangle-shaped part has a first side being yet another side of the fourth projection face and a second side being a second part of said another side of the fourth projection face, the first side of the second right-triangle-shaped part has contact with another side of the first triangular projection face, the first side of the first right-triangle-shaped part has contact with another side of the third triangular projection face, there is an image content discontinuity boundary between the first side of the second right-triangle-shaped part and said another side of the first triangular projection face, and there is an image content discontinuity boundary between the first side of the first right-triangle-shaped part and said another side of the third triangular projection face.
This invention relates to a method for projecting and assembling triangular faces into an octahedron layout, particularly for visualizing spherical content such as panoramic images or 3D environments. The problem addressed is the efficient and seamless arrangement of projection faces derived from a viewing sphere to minimize image distortion and discontinuities when rendering spherical content in a rectangular layout. The method involves projecting a hemisphere onto an octahedron, resulting in triangular projection faces. These faces are arranged in a rectangular layout, where a fourth projection face is derived from the hemisphere and split into two right-triangle-shaped parts. The first right-triangle part has one side aligned with the full side of the fourth projection face and another side split into two segments. The second right-triangle part similarly has one side aligned with another side of the fourth projection face and shares a boundary with the first triangular projection face. The first right-triangle part shares a boundary with the third triangular projection face. Discontinuity boundaries are introduced between the right-triangle parts and adjacent triangular faces to manage image transitions. This arrangement ensures minimal distortion and seamless transitions when rendering spherical content in a rectangular format.
9. The method of claim 6 , wherein the triangular projection faces assembled in the octahedron projection layout further comprise a fourth projection face derived from the first hemisphere via the octahedron projection of the viewing sphere, a first padding area extended from one side of the fourth triangular projection face has contact with a second padding area extended from another side of the third triangular projection face, the first padding area comprises padding pixels derived from boundary pixels of said one side of the fourth triangular projection face, the second padding area comprises padding pixels derived from boundary pixels of said another side of the third triangular projection face, and there is an image content discontinuity boundary between the first padding area and the second padding area.
This invention relates to a method for generating and assembling triangular projection faces in an octahedron projection layout for spherical content, addressing issues of image discontinuity at seams between adjacent projection faces. The method involves deriving a fourth triangular projection face from a first hemisphere of a viewing sphere using an octahedron projection technique. The fourth projection face is part of an octahedron layout, which includes at least a third triangular projection face derived from the same hemisphere. To mitigate visual artifacts at the boundaries between adjacent faces, the method introduces padding areas on opposite sides of the fourth and third projection faces. The first padding area, extending from one side of the fourth face, contains padding pixels derived from boundary pixels of that side, while the second padding area, extending from another side of the third face, contains padding pixels derived from boundary pixels of that side. These padding areas overlap or meet at an image content discontinuity boundary, ensuring smooth transitions between adjacent projection faces. The technique is particularly useful in spherical content rendering, such as panoramic imaging or virtual reality, where seamless stitching of projection faces is critical for visual quality.
10. The method of claim 6 , wherein a shape of the octahedron projection layout is a rectangle, the triangular projection faces assembled in the octahedron projection layout further comprise a fourth projection face derived from the first hemisphere via the octahedron projection of the viewing sphere, the fourth projection face is split into a first right-triangle-shaped part and a second right-triangle-shaped part, the first right-triangle-shaped part has a first side being one side of the fourth projection face and a second side being a first part of another side of the fourth projection face, the second right-triangle-shaped part has a first side being yet another side of the fourth projection face and a second side being a second part of said another side of the fourth projection face, a first padding area is extended from the first side of the second right-triangle-shaped part has contact with a second padding area that is extended from another side of the first triangular projection face, a third padding area is extended from the first side of the first right-triangle-shaped part and has contact with a fourth padding area that is extended from another side of the third triangular projection face, the first padding area comprises padding pixels derived from boundary pixels of the first side of the second right-triangle-shaped part, the second padding area comprises padding pixels derived from boundary pixels of said another side of the first triangular projection face, the third padding area comprises padding pixels derived from boundary pixels of the first side of the first right-triangle-shaped part, the fourth padding area comprises padding pixels derived from boundary pixels of said another side of the third triangular projection face, there is an image content discontinuity boundary between the first padding area and the second padding area, and there is an image content discontinuity boundary between the third padding area and the fourth padding area.
This invention relates to a method for generating a rectangular octahedron projection layout from a viewing sphere, particularly for 360-degree image or video content. The method addresses the challenge of seamlessly stitching together triangular projection faces derived from an octahedron projection of a hemisphere, ensuring minimal visual discontinuities at the boundaries. The octahedron projection layout consists of triangular faces assembled into a rectangular shape. A fourth projection face, derived from the first hemisphere, is split into two right-triangle-shaped parts. The first part has one side as a full side of the fourth projection face and another side as a portion of an adjacent side. The second part has one side as another full side of the fourth projection face and another side as the remaining portion of the adjacent side. Padding areas are extended from the sides of these triangular parts and adjacent projection faces. The first padding area, derived from boundary pixels of the second right-triangle-shaped part, contacts the second padding area from an adjacent triangular face. Similarly, the third padding area from the first right-triangle-shaped part contacts the fourth padding area from another adjacent triangular face. These padding areas help mitigate discontinuities at the boundaries, though image content discontinuities may still exist between them. The method ensures that the padding areas are filled with pixels derived from the boundary regions of the respective projection faces, reducing visible seams in the final rectangular layout.
11. The method of claim 3 , wherein the viewing sphere is composed of a first hemisphere and a second hemisphere; the first triangular projection face and the second triangular projection face are both derived from the first hemisphere via the octahedron projection of the viewing sphere, and the third triangular projection face is derived from the second hemisphere via the octahedron projection of the viewing sphere.
This invention relates to a method for projecting a viewing sphere onto a set of triangular projection faces using an octahedron projection technique. The method addresses the challenge of efficiently mapping a spherical surface onto planar faces for applications such as panoramic imaging, virtual reality, or 3D rendering. The viewing sphere is divided into two hemispheres: a first hemisphere and a second hemisphere. The first hemisphere is projected onto a first triangular projection face and a second triangular projection face using an octahedron projection. Similarly, the second hemisphere is projected onto a third triangular projection face via the same octahedron projection method. The octahedron projection ensures minimal distortion while mapping the spherical surface onto the triangular faces, preserving geometric accuracy and visual fidelity. The triangular projection faces are derived from the hemispheres by applying the octahedron projection, which involves decomposing the sphere into eight triangular faces arranged in a symmetric octahedral configuration. This approach simplifies the representation of spherical data while maintaining compatibility with existing rendering pipelines. The method is particularly useful in applications requiring efficient storage and processing of spherical content, such as immersive media or computer graphics.
12. The method of claim 1 , wherein a shape of each of the triangular projection faces is an isosceles right triangle.
This invention relates to a method for optimizing the design of a three-dimensional object with triangular projection faces, particularly for applications in additive manufacturing or structural engineering. The problem addressed is improving the structural integrity and manufacturability of objects with complex geometries by ensuring uniform stress distribution and minimizing material waste. The method involves generating triangular projection faces on the surface of the object, where each triangular face is an isosceles right triangle. This specific triangular shape ensures consistent geometric properties, such as equal angles and predictable side lengths, which enhance structural stability. The isosceles right triangle configuration allows for efficient load distribution, reducing stress concentrations and improving overall mechanical performance. Additionally, this shape simplifies the manufacturing process by standardizing the geometric elements, making it easier to fabricate using techniques like 3D printing or laser cutting. The triangular faces are arranged in a pattern that covers the object's surface, ensuring full coverage while maintaining structural integrity. The method may also include adjusting the size or orientation of the triangles to optimize material usage or mechanical properties. This approach is particularly useful in applications requiring lightweight yet strong structures, such as aerospace components, automotive parts, or architectural elements. By using isosceles right triangles, the method ensures both functional and manufacturing advantages over other triangular configurations.
13. The method of claim 12 , wherein each of the triangular projection faces has a first side, a second side and a third side, and an equator of the viewing sphere is mapped along first sides of the triangular projection faces.
This invention relates to a method for projecting a spherical image onto a plurality of triangular projection faces, addressing the challenge of efficiently mapping spherical content onto planar surfaces for display or processing. The method involves arranging multiple triangular projection faces in a specific configuration to minimize distortion when rendering a spherical image. Each triangular face has three sides, and the equator of the viewing sphere is aligned with the first sides of these triangular faces. This alignment ensures that the equatorial region of the spherical image is accurately represented without distortion. The triangular faces are arranged such that their second and third sides form angles that facilitate seamless stitching of adjacent faces, preserving the spherical geometry. The method may also include adjusting the projection parameters to optimize image quality and reduce artifacts. This approach is particularly useful in applications requiring high-fidelity spherical image rendering, such as virtual reality, panoramic imaging, and 3D visualization systems. The invention provides a structured way to decompose a spherical image into planar segments while maintaining geometric accuracy and minimizing distortion.
14. The method of claim 12 , wherein an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces.
This invention relates to a method for projecting a viewing sphere onto a polyhedral surface, specifically addressing the challenge of minimizing distortion when mapping spherical content onto flat or curved surfaces. The method involves dividing the viewing sphere into multiple triangular projection faces, where each face is a portion of the sphere's surface. The key innovation is that the equator of the viewing sphere is not aligned with any side of these triangular projection faces. This prevents the equator from being mapped along straight edges, which would otherwise introduce significant distortion. Instead, the equator is distributed across multiple faces, ensuring a more uniform and accurate representation of the spherical content. The method may also include adjusting the shape or size of the triangular faces to further reduce distortion, particularly near the poles of the sphere. This approach is useful in applications such as virtual reality, panoramic imaging, and spherical display systems, where minimizing geometric distortion is critical for a high-quality viewing experience. The invention improves upon existing projection techniques by avoiding the common issue of equatorial misalignment, which can cause visual artifacts and inaccuracies in the projected image.
15. The method of claim 12 , wherein the viewing sphere is composed of a first hemisphere and a second hemisphere; and the first triangular projection face, the second triangular projection face and the third triangular projection face are all derived from the first hemisphere via the octahedron projection of the viewing sphere.
This invention relates to a method for generating a three-dimensional (3D) projection of a viewing sphere, particularly for applications in virtual reality, computer graphics, or immersive displays. The problem addressed is the efficient and accurate representation of a spherical viewing space using planar projections, which is essential for rendering panoramic or immersive visual content. The method involves dividing the viewing sphere into two hemispheres—a first hemisphere and a second hemisphere. The first hemisphere is then projected onto an octahedron, a polyhedron with eight triangular faces, to derive three triangular projection faces. These triangular faces serve as planar representations of portions of the spherical surface, enabling simplified rendering and processing of the 3D content. The second hemisphere may be similarly processed, though the claim focuses on the first hemisphere's projection. By using an octahedron projection, the method ensures minimal distortion and efficient mapping of spherical content onto flat surfaces, which is critical for applications requiring high-fidelity visual output. The approach simplifies the computational complexity of handling spherical data while maintaining visual accuracy. This technique is particularly useful in systems where spherical content must be displayed or processed in a planar format, such as in VR headsets, panoramic cameras, or 3D modeling software.
16. The method of claim 15 , wherein a shape of the octahedron projection layout is a rectangle, the first triangular projection face is split into a first right-triangle-shaped part and a second right-triangle-shaped part that are assembled in the octahedron projection layout with different orientations respectively, the first right-triangle-shaped part has a first side being said one side of the first projection face and a second side being a first part of another side of the first projection face, the second right-triangle-shaped part has a first side being yet another side of the first projection face and a second side being a second part of said another side of the first projection face, the third triangular projection face is split into a third right-triangle-shaped part and a fourth right-triangle-shaped part that are assembled in the octahedron projection layout with different orientations respectively, the third right-triangle-shaped part has a first side being said one side of the third projection face and a second side being a first part of another side of the third projection face, and the fourth right-triangle-shaped part has a first side being yet another side of the third projection face and a second side being a second part of said another side of the third projection face.
This invention relates to a method for projecting and assembling triangular faces into an octahedron layout, specifically addressing the challenge of efficiently organizing and orienting triangular projection faces to form a rectangular octahedron structure. The method involves splitting a first triangular projection face into two right-triangle-shaped parts with different orientations. The first right-triangle-shaped part has one side as a side of the original triangular face and another side as a portion of an adjacent side. The second right-triangle-shaped part has one side as another side of the original triangular face and another side as the remaining portion of the adjacent side. Similarly, a third triangular projection face is split into two right-triangle-shaped parts with different orientations. The third right-triangle-shaped part has one side as a side of the original triangular face and another side as a portion of an adjacent side. The fourth right-triangle-shaped part has one side as another side of the original triangular face and another side as the remaining portion of the adjacent side. These split parts are then assembled in the octahedron projection layout to form a rectangular structure. This approach ensures precise alignment and orientation of the triangular faces, enabling accurate construction of the octahedron. The method is particularly useful in applications requiring geometric precision, such as 3D modeling, architectural design, and structural engineering.
17. The method of claim 15 , wherein a shape of the octahedron projection layout is a rectangle, the triangular projection faces assembled in the octahedron projection layout further comprise a fourth triangular projection face derived from the first hemisphere via the octahedron projection of the viewing sphere, one side of the fourth triangular projection face has contact with another side of the first triangular projection face, another side of the fourth triangular projection face has contact with another side of the third triangular projection face, there is an image content continuity boundary between said one side of the fourth triangular projection face and said another side of the first triangular projection face, and there is an image content continuity boundary between said another side of the fourth triangular projection face and said another side of the third triangular projection face.
This invention relates to a method for projecting and assembling image content onto an octahedron layout, specifically for visualizing data on a spherical surface. The method addresses the challenge of mapping spherical data onto a planar or polyhedral structure without distortion or discontinuities. The octahedron projection layout is rectangular, consisting of triangular projection faces derived from a hemisphere via an octahedron projection of a viewing sphere. The layout includes a fourth triangular projection face, which is adjacent to a first and third triangular projection face. One side of the fourth face contacts a side of the first face, and another side contacts a side of the third face. Image content continuity boundaries exist between these contacting sides, ensuring seamless transitions between adjacent faces. This configuration allows for efficient rendering and visualization of spherical data while maintaining geometric and visual coherence. The method is particularly useful in applications requiring high-fidelity spherical projections, such as virtual reality, geospatial mapping, and scientific visualization.
18. The method of claim 1 , wherein at least one picture boundary resulting from filling of dummy areas in the projection-based frame or at least one image content discontinuity boundary resulting from assembling of the triangular projection faces in the octahedron projection layout has a jagged shape with each jag being even-pixel wide.
This invention relates to image processing techniques for projection-based frame rendering, particularly addressing visual artifacts in panoramic or 360-degree image generation. The method focuses on improving the appearance of boundaries between image segments or dummy-filled areas in an octahedron projection layout, which is commonly used for spherical or panoramic image mapping. The problem being solved involves jagged or uneven edges that occur when assembling triangular projection faces or filling dummy areas, which can degrade visual quality. The method ensures that any jagged boundaries resulting from these processes have an even-pixel width for each jag, meaning the irregularities in the edges are uniform in terms of pixel count. This uniformity helps reduce visual distortion and improves the seamless integration of image segments. The technique applies to both the boundaries formed by filling dummy areas (unused regions in the projection frame) and the discontinuities that arise when combining triangular projection faces in the octahedron layout. By enforcing even-pixel-wide jags, the method minimizes perceptible artifacts, leading to a smoother and more coherent final image. This approach is particularly useful in applications requiring high-quality panoramic imaging, such as virtual reality, 3D rendering, and immersive media.
19. The method of claim 12 , wherein the viewing sphere is composed of a first hemisphere and a second hemisphere; the first triangular projection face and the second triangular projection face are both derived from the first hemisphere via the octahedron projection of the viewing sphere, and the third triangular projection face is derived from the second hemisphere via the octahedron projection of the viewing sphere.
This invention relates to a method for projecting a three-dimensional viewing sphere onto a two-dimensional surface using an octahedron-based projection technique. The method addresses the challenge of accurately representing a spherical surface in a planar format while minimizing distortion, particularly in applications such as virtual reality, computer graphics, or geospatial mapping. The viewing sphere is divided into two hemispheres, each processed separately to generate distinct triangular projection faces. The first and second triangular projection faces are derived from the first hemisphere through an octahedron projection of the viewing sphere. Similarly, the third triangular projection face is derived from the second hemisphere using the same octahedron projection method. This approach ensures that the spherical surface is uniformly mapped onto the planar surface, reducing distortion and maintaining geometric accuracy. The octahedron projection technique involves projecting the spherical surface onto the faces of an octahedron, which is then unfolded into a two-dimensional net. This method leverages the symmetry of the octahedron to preserve angular relationships and minimize area distortion. The resulting triangular projection faces can be used for rendering, analysis, or further processing in various computational applications. The invention improves upon existing projection methods by providing a more efficient and accurate representation of spherical data in a planar format.
20. A processing circuit for generating a projection-based frame, comprising: an input interface, arranged to receive an omnidirectional video frame corresponding to a viewing sphere; and a conversion circuit, arranged to generate the projection-based frame according to the omnidirectional video frame and an octahedron projection layout, wherein the projection-based frame has a 360-degree image content represented by triangular projection faces assembled in the octahedron projection layout, and a 360-degree image content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere; wherein the triangular projection faces assembled in the octahedron projection layout comprise a first triangular projection face, a second triangular projection face and a third triangular projection face, one side of the first triangular projection face has contact with one side of the second triangular projection face, one side of the third triangular projection face has contact with another side of the second triangular projection face, there is an image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, and there is an image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face; wherein the triangular projection faces of the octahedron projection layout are obtained from the octahedron projection of the viewing sphere according to an octahedron; a boundary between one side of a first face of the octahedron and one side of a second face of the octahedron corresponds to the image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, where said one side of the first face of the octahedron connects with said one side of the second face of the octahedron; and a boundary between one side of a third face of the octahedron and another side of the second face of the octahedron corresponds to the image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face, where said one side of the third face of the octahedron connects with said another side of the second face of the octahedron.
This invention relates to a processing circuit for generating a projection-based frame from omnidirectional video data, specifically using an octahedron projection layout. The technology addresses the challenge of efficiently representing 360-degree image content from a viewing sphere in a structured format suitable for processing and display. The circuit includes an input interface to receive omnidirectional video frames and a conversion circuit that generates a projection-based frame by mapping the 360-degree content onto triangular projection faces arranged in an octahedron layout. The projection faces are derived from an octahedron projection of the viewing sphere, where the 360-degree image content is divided into triangular segments. The layout includes at least three triangular projection faces: a first, second, and third face, where the first and second faces share a side with an image content continuity boundary, and the second and third faces share another side with a similar boundary. These boundaries correspond to the edges where adjacent faces of the octahedron meet, ensuring seamless transitions between segments. The octahedron projection method ensures that the spherical image content is accurately mapped onto the triangular faces while maintaining geometric and visual continuity. This approach optimizes storage and processing efficiency for omnidirectional video applications.
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May 5, 2020
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